The pattern is written for 2 different gauges (onesize and onesize+) they will have the same finished measurements. Substituting the yarn should as a result be easier, even when knitting with the same size needles. If your gauge isn’t correct try with larger or smaller needles – If the gauge fits the measurements will be correct! NB! If you get less stitches pr. 10 cm /4” the poncho will be bigger, if you get more stitches pr. 10 cm/4” the poncho will be smaller._____________________________________________